Objectives

Our aims

NACLIM aims at investigating and quantifying the predictability on interannual to decadal time scales of the climate in the North Atlantic/European sector related to North Atlantic/Arctic Ocean surface state (SST and sea ice) variability and change. NACLIM will partly build on the multi-model decadal prediction experiments currently performed by a number of leading European and worldwide research institutions as part of the Coupled Model Intercomparison Project Phase 5 (CMIP5). Rather than running climate forecasts within the project, we will analyze the CMIP5 predictions and critically assess their
quality
for the near-future stage of atmospheric and oceanic quantities.

In particular, we want:

Eleven objectives for one project

Obj. Nr. and Title Associated deliverables
1. Assessing the predictability and quantifying the uncertainty in forecasts of the North Atlantic/Arctic Ocean surface state Associated deliverables D25, D36, D56, D37, D48, D19, D38, D14, D29, D44, D55, D15, D27
Using the CMIP5 multi-model hindcast and forecast experiments, we will assess the predictability of the North Atlantic/Arctic ocean surface state (SST and sea ice), as well as of key quantities in the oceanic part controlling it. Such model analysis, combined with integrated observations of oceanic fluxes and water mass formation, will be used to quantify the uncertainty in near-future predictions.
2. Assessing the atmospheric predictability related to the North Atlantic/Arctic Ocean surface state Associated deliverables D18, D37, D48, D49, D50
A newly developed adjoint assimilation system, available observational datasets, and atmospheric reanalysis products as well as atmosphere, ocean and coupled climate models will be used to identify North Atlantic/Arctic Ocean surface state changes that most strongly impact the atmosphere in the North Atlantic/European sector, to quantify their climatic impact, and to assess the related atmospheric predictability. Underlying mechanisms and the back interaction of the atmospheric response on the ocean will be investigated. Atmospheric predictions will be empirically downscaled to local scales of interest for impact studies.
3. Monitoring of volume, heat and fresh water transports across key sections in the North Atlantic Associated deliverables D12, D24, D32, D34, D53, D57, D6, D31, D15, D16, D17, D30, D46
The existing observational timeAssociated deliverables D12, D24, D32, D34, D53, D57, D6, D31, D15, D16, D17, D30, D46 series of volume, heat and fresh water exchanges across the Greenland-Scotland-Ridge, and in the fluxes in the deep western boundary currents subtropics at 26°N will be extended to durations that may permit identification of potential decadal variability and trends. Contributions will be provided to fill the existing gap of observing the basin-wide transports in the subpolar North Atlantic.
4. Quantifying the benefit of the different ocean observing system components for the initialization of decadal climate predictions Associated deliverables D9, D26, D39, D58, D28
The impact of the different components of the existing ocean observing system and its potential extensions in terms of decadal hindcast skill will be quantified using hindcast experiments in an ideal model world. Necessary enhancements and potential reductions of the present observing system will be identified.
5. Establishing the impact of an Arctic initialization on the forecast skill in the North Atlantic/European sector Associated deliverables D18, D38, D47, D10, D40, D51
The forecast skill of a newly developed adjoint assimilation system will be improved by using observations in the Arctic sector to better constrain uncertain model parameters. Sources of the predictive skill due to initializing the Arctic Ocean and sea ice will be identified by comparing the potential predictability across a perfect model ensemble, with data withholding experiments using a state-of-the-art coupled climate model.
6. Quantifying the impact of predicted North Atlantic upper ocean state changes on the oceanic ecosystem Associated deliverables D11, D41, D52
The predictability as well as forecasts of the near-future state and the reliability of these forecasts will be investigated for case studies from different trophic levels of the northeastern North Atlantic marine ecosystem, by combining the CMIP5 decadal prediction experiments with existing knowledge of physical – biological links.
7. Quantifying the impact of predicted North Atlantic upper ocean state changes on socio-economic systems in European urban societies Associated deliverables D20, D33, D42
The spatially coarse resolution CMIP5 decadal prediction experiments will be downscaled to the urban scale, by means of a newly developed deterministic urban climate model. The resulting high resolution urban climate fields will be analyzed, and coupled to relevant socio-economic data, focusing on human health.
8. Recommendations for observational and prediction systems Associated deliverables D8, D54, D38, D50, D12, D32, D15, D27, D51, D52
Based on the scientific results regarding the benefit of the different ocean observing system components for the initialization of decadal prediction systems, as well as the impact of initializing the Arctic on the forecast skill over Europe, recommendations will be made to optimize the present ocean observing system, and to best initialize the model-based prediction systems, in order to enhance decadal predictive skill in the North Atlantic/European sector.
9. Recommendations for predictions of the oceanic ecosystem Associated deliverables D52, D11, D41
Based on the scientific results regarding the predictability of the north-eastern North Atlantic marine ecosystem, recommendations will be made for future research requirements necessary to convert predictions of ocean physics into predictions of the marine biological environment.
10. Dissemination of key results to the climate service community and relevant end-users/stakeholders. Associated deliverables D3, D5, D54, D6, D7, D13, D24, D55, D21, D53, D021, D022, D023
The bridge between the scientific institutions and potential end-users (such as policy- and decision-makers, the private sector or the industry) will be built. The NACLIM management partners will establish a close communication between the NACLIM scientists and the end-users, to make sure that specific needs for information are identified and to allow feed-backs on these needs. This will be achieved through the set up of a coordination and clustering mechanism for the EUPORIAS, NACLIM and SPECS projects.
11. Constructing a dataset for sea surface and sea ice surface temperatures in the Arctic Associated deliverables D28, D40
A new and innovative 15-year long dataset combining satellite sea surface and sea ice surface temperatures covering the entire Arctic Ocean will be constructed. This dataset will help to better initialize the Arctic in model-based decadal prediction systems.